Sample collection and handling in a fluid environment is of course the subject of a variety of reports. Marine research typically requires continuous information on the marine food chain which may generally consist of (1) aquatic bacteria and protists, (2) phytoplankton (3) zooplankton and (4) fish as well as higher forms, crustaceans, reptiles, marine mammals, etc., where each may become a food source for the next in ascending order. Bacteria, protists, phytoplankton and zooplankton may be measured in oceans and studied for their dependence and effect on fisheries and environmental health. Information may be required on their abundance and vertical and horizontal distributions in continental shelf waters, deep oceans and inland waters. Acquiring the data accurately, continuously and with wide spatial coverage remains an on-going problem.
It can be noted that the U.S. Coast Guard, for purposes of operationally defining relevant classes of organisms (from the perspective of invasive species in shipping ballast water) is as follows: zooplankton—organisms that are ≧50 μm in minimum dimension; phytoplankton/protozoa—organism that are <50 μm and ≧10 μm; bacteria—organisms <10 μm in minimum dimension (this operational group will also include many of the smaller phototrophic phytoplankton and blue-green bacteria).
Accordingly, a need exists for a method and apparatus that may automate the collection of samples for critical assays, including enumeration, phylogenetic identity, molecular and metabolic functioning and viability of the various microbial, phytoplankton and zooplankton components of the food chain. More particularly, the method may comprise automated in situ rate studies involving tracer incubations and sample preservation.